src/plugins/apt.sml

   1 (* HCoop Domtool (http://hcoop.sourceforge.net/)
   2  * Copyright (c) 2006-2007, Adam Chlipala
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *)
  18
  19 (* APT package database querying *)
  20
  21 structure Apt :> APT = struct
  22
  23 fun validName s = CharVector.all (fn ch => Char.isAlphaNum ch orelse ch = #"_" orelse ch = #"-" orelse ch = #".") s
  24                   andalso (size s > 0 andalso String.sub (s, 0) <> #"-")
  25
  26 fun installed name =
  27     validName name
  28     andalso let
  29         val proc = Unix.execute ("/usr/bin/apt-cache", ["policy", name])
  30         val inf = Unix.textInstreamOf proc
  31
  32         val _ = TextIO.inputLine inf
  33     in
  34         (case TextIO.inputLine inf of
  35              NONE => false
  36            | SOME line =>
  37              case String.tokens Char.isSpace line of
  38                  [_, "(none)"] => false
  39                | [_, _] => true
  40                | _ => false)
  41         before ignore (Unix.reap proc)
  42     end
  43
  44 end